Renault's Fernando Alonso took a huge step towards becoming Formula One's youngest champion by seizing pole position for what could be a title-deciding Brazilian Grand Prix.

McLaren's Kimi Raikkonen, the only man standing between 24-year-old Alonso and the title, made an error under pressure at the first corner in Saturday's qualifying and starts on the third row in fifth place.

"The weekend has started in a good way," said Alonso, who need only finish third to secure the crown on Sunday even if his Finnish rival wins, after his fifth pole from 17 races this season.

"The car is competitive enough to be on the podium...we have a perfect opportunity tomorrow."

Raikkonen is 25 points behind Alonso and his chances, already slim, of keeping the title fight alive must now rest on the Spaniard tripping up.

That is always a possibility at Interlagos and Alonso also has Raikkonen's Colombian team mate Juan Pablo Montoya, race winner for Williams last year at Interlagos, alongside.

"I think we've got a very good strategy for the race and we are looking quite strong," said Montoya. "Kimi's going to have a tough race tomorrow but I think from where I'm standing it would be good to win."

ANYTHING POSSIBLE

Raikkonen was last to run in qualifying after winning the Belgian Grand Prix two weeks ago, his sixth victory of the year, but a puff of smoke from a locked wheel under braking betrayed the Finn's error.

"That was a shame," said the Finn. "I did what I could to make up for the mistake and I believe that without that I could have been on pole.

"I now focus on the race where anything is possible. We will just go for it and do what we can."

Renault's Italian Giancarlo Fisichella was third, another boost for his team who are just six points ahead of McLaren in the constructors' standings, with Briton Jenson Button a strong fourth for BAR.

Fisichella's position was all the more remarkable as the Roman was first out on track when conditions were less favourable.

Raikkonen lines up alongside Austrian Christian Klien, who recovered from a crash in Friday practice to hand Red Bull one of their best qualifying results of the year.

Japan's Takuma Sato, in a BAR, did not complete a timed lap due to a 10-place penalty incurred after he collided with Ferrari's seven-times champion Michael Schumacher in Belgium.

Schumacher qualified seventh and starts alongside his future Ferrari team mate Felipe Massa in a Sauber.

Toyota's Italian Jarno Trulli would have been on the fourth row but collected a 10-place penalty for an engine change, dropping him to 18th.

Williams, who have not won since Brazil last year, had an afternoon to forget with Australian Mark Webber and Brazilian Antonio Pizzonia 14th and 15th with the Jordan of Portugal's Tiago Monteiro ahead of them.

"This qualifying result is more than disappointing," said BMW motorsport director Mario Theissen.

"In a normal race, it would be very tough to get any points from these grid positions."